feat(test): retry pacstrap through transient mirror flakes

test-install.sh aborts a whole 5-minute VM run when pacstrap hits a transient mirror blip, and the suite reports a failure indistinguishable from a real install regression. run_test now retries the install up to twice, but only when the in-VM log shows both pacstrap's "Failed to install packages to new root" marker and a download/network indicator. A deterministic failure like "target not found" carries the marker without a network indicator, so it still fails fast. archangel's failure trap exports the pool and unmounts on abort, so each retry re-partitions and re-pacstraps from a clean state.

Wiring the predicate up needed a source-guard so bats can source the harness, which had none. With that in place I unit-covered the pure helpers — is_transient_install_failure, char_to_qemu_key, get_disk_count, get_disk_args — and lifted char_to_qemu_key out of monitor_sendkeys so the QEMU keymap is testable on its own.

The keymap test found a dead branch. The backslash case pattern was '\\', which never matches a lone backslash because bash matches one against '\', so a passphrase containing a backslash would have sent an invalid QEMU keyname instead of "backslash". No test passphrase uses one, so it never bit. I fixed the pattern.

0 files changed, 0 insertions, 0 deletions